They were disabled at 53b8d93 ("grep: disable threading in non-worktree
case", 12-12-2011), due to observable perfomance drops. But now that
zlib inflation can be performed in parallel, we can regain the speedup.
Grep'ing 'abcd[02]' ("Regex 1") and '(static|extern) (int|double) \*'
("Regex 2") at chromium's repository[1] I got:
Threads | Regex 1 | Regex 2
---------|------------|-----------
1 | 17.5815s | 21.7217s
2 | 9.7983s | 11.3965s
8 | 6.3097s | 6.9667s
These are all means of 30 executions after 2 warmup runs. All tests were
executed on a i7-7700HQ with 16GB of RAM and SSD.
[1]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
04-06-2019), after a 'git gc' execution.
Signed-off-by: Matheus Tavares <matheus.bernardino@xxxxxx>
---
builtin/grep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/builtin/grep.c b/builtin/grep.c
index 682e2461d0..9309dea833 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -1046,7 +1046,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
pathspec.recursive = 1;
pathspec.recurse_submodules = !!recurse_submodules;
- if (list.nr || cached || show_in_pager) {
+ if (show_in_pager) {
if (num_threads > 1)
warning(_("invalid option combination, ignoring --threads"));
num_threads = 1;
--
2.22.0
